STAT3 protects from liver injury and fibrosis in a mouse model of sclerosing cholangitis

ABSTRACT: Background and aims: Signal transducer and activator of transcription 3 (Stat3) is the main mediator of interleukin-6 type cytokine signaling required for hepatocyte proliferation and hepatoprotection but its role in sclerosing cholangitis and other cholestatic liver diseases remains unresolved. Methods: We investigated the role of Stat3 in inflammation-induced cholestatic liver injury and used mice lacking the multidrug resistance gene 2 (mdr2-/-) as a model for SC. Results: We demonstrate that conditional inactivation of stat3 in hepatocytes and cholangiocytes (stat3 delta hc) of mdr2-/- mice strongly aggravated bile acid-induced liver injury and fibrosis. A similar phenotype was observed in mdr2-/- mice lacking IL-6 production. Biochemical and molecular characterization suggested that Stat3 exerts hepatoprotective functions in both, hepatocytes and cholangiocytes. Loss of Stat3 in cholangiocytes led to increased expression of TNFα which might reduce the barrier function of bile ducts. Loss of Stat3 in hepatocytes led to upregulation of bile acid biosynthesis genes and downregulation of hepatoprotective epidermal growth factor receptor and insulin-like growth factor 1 signaling pathways. Consistently, stat3deltahc mice were more sensitive to cholic acid-induced liver damage than control mice. Conclusions: Our data suggest that Stat3 prevents cholestasis and liver damage in sclerosing cholangitis via regulation of pivotal functions in hepatocytes and cholangiocytes. Affymetrix microarray analyses was performed to identify metabolic and molecular pathways in stat3Dhc mdr2-/- mice that lead to cholestasis and bile acid-induced liver injury. To avoid false positive results that are due to differential cellular composition, we defined the onset of fibrosis and expression of fibrogenic factors in stat3Dhc mdr2-/- mice.

ORGANISM(S): Mus musculus

SUBMITTER: Stefanie Tauber 

PROVIDER: E-GEOD-18759 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress